The concern over toxic waste entering ground water supplies has resulted in a dramatic increase in the number of ground water investigations. Heretofore, most of the investigations have required the installation of water quality monitoring wells to determine if ground water contamination exists and to define or map the vertical and horizontal extent of the contamination. The cost of installing monitoring wells is high and hence geophysical techniques have been used to minimize the number of monitoring wells. High resolution of geophysical surveys are expensive and are not always accurate in determining the locations and contaminant concentrations. As a result, more wells must be provided because of improperly placed or too few monitoring wells.